Redundant Array of Independent Disks (RAID) is a data backup technology, which can combine a plurality of independent physical disks in different manners to form a disk array (that is logical disks) so as to provide a better storage performance and higher reliability than a single disk. In order to restore data when a certain disk in the RAID fails, the RAID is typically provided with one parity check information block (such as RAID 1, RAID 3, RAID 5 or the like) or two or more parity check information blocks (such as RAID 6) and so forth.
Taking RAID 5 as an example, if a certain disk in the RAID fails, a new disk is added to the RAID. Then, the RAID can calculate the data in the failed disk by use of distribution check information, and rebuild the data in the new disk to restore the data. However, in the process of rebuilding the failed disk, if a further disk also fails, data loss in the RAID will be caused, thereby decreasing the reliability of the RAID.